Tube joint and apparatus for producing the same

ABSTRACT

A ring member and ring members made of metal are tightened and installed to the outer circumferential surface of a body made of a resin material. Accordingly, the body is prevented from outward deformation. When a tube joint is used in a high temperature atmosphere, even if any force acts on a fluid tube in the direction to cause detachment from the tube joint due to any external force or the pressure fluid flowing through the inside of the tube joint, then the fluid tube and a connecting member inserted into the body are reliably prevented from disengagement.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a tube joint and a method forproducing the same for connecting a fluid tube to a pressurefluid-driven apparatus such as a solenoid-operated valve and a cylinder,the fluid tube being formed with a passage for introducing anddischarging a pressure fluid or the like.

[0003] 2. Description of the Related Art

[0004] The tube joint has been hitherto used to connect and couple afluid tube to a pressure fluid-driven apparatus such as asolenoid-operated valve and a cylinder. Those known as such a tube jointinclude a tube joint which has a body made of a resin material forinserting a fluid tube thereinto.

[0005] However, the tube joint concerning the conventional technique asdescribed above involves the following fear as compared with a tubejoint which has a body made of a metal material. That is, when the tubejoint is used in a high temperature atmosphere, the body made of theresin material tends to cause deformation outwardly. The fluid tube maybe disengaged from the tube joint when any force acts on the fluid tubein the direction to cause detachment from the tube joint due to anyexternal force or the pressure fluid flowing through the inside of thetube joint.

[0006] It is also feared that when any external force such as shock isexerted on the body made of the resin material, the body may be detachedfrom a connecting member screwed into the pressure fluid-drivenapparatus.

SUMMARY OF THE INVENTION

[0007] A general object of the present invention is to provide a tubejoint which makes it possible to prevent a fluid tube formed with apassage for allowing a fluid to pass therethrough from disengagementfrom a body made of a resin material.

[0008] A principal object of the present invention is to provide a tubejoint which makes it possible to prevent a body made of a resin materialfrom detachment from a connecting member screwed into a pressurefluid-driven apparatus.

[0009] Another object of the present invention is to provide anapparatus for producing a tube joint, which makes it possible toconveniently tighten a ring member to be fitted to the outercircumferential surface of a body.

[0010] The above and other objects, features, and advantages of thepresent invention will become more apparent from the followingdescription when taken in conjunction with the accompanying drawings inwhich a preferred embodiment of the present invention is shown by way ofillustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 shows a front view illustrating a tube joint according toan embodiment of the present invention;

[0012]FIG. 2 shows a longitudinal sectional view taken along the axialdirection of the tube joint shown in FIG. 1;

[0013]FIG. 3 shows an exploded perspective view illustrating the tubejoint shown in FIG. 1;

[0014]FIG. 4 shows a longitudinal sectional view illustrating atightening apparatus for tightening a ring member to be installed to thetube joint shown in FIG. 1;

[0015]FIG. 5 shows, with partial omission, a perspective viewillustrating the tightening apparatus shown in FIG. 4;

[0016]FIG. 6 shows a partial magnified longitudinal sectional viewillustrating the tightening apparatus shown in FIG. 4 and a connectingmember;

[0017]FIG. 7 shows a partial magnified longitudinal sectional viewillustrating the tightening apparatus shown in FIG. 4 and anattachment/detachment mechanism; and

[0018]FIG. 8 shows a method for using the tightening apparatus shown inFIG. 4, illustrating a longitudinal sectional view depicting a state inwhich a tightening member tightens the ring member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] With reference to FIGS. 1 and 2, reference numeral 10 indicates atube joint according to an embodiment of the present invention. The tubejoint 10 has a cylindrical body 12 made of a resin material which isformed to have a substantially L-shaped bent configuration. A passage 13is formed through the body 12. A connecting member 14, which is made ofa metal material and which has a passage 15 for allowing a fluid to passtherethrough, is fitted to the first end side of the body 12. An annularexpanded section 16, which has a sharp cross section, is formed on theouter circumference of the connecting member 14. The annular expandedsection 16 bites into the inner wall surface of the body 12, and thusthe connecting member 14 is prevented from disengagement from the body12.

[0020] An O-ring 20 is installed in an annular groove disposed at aportion of connection between the body 12 and the connecting member 14.Thus, the pressure fluid, which passes through the inside of the body12, is prevented from leakage. A male thread 22 is formed on the outercircumference on the end side of the connecting member 14. The tubejoint 10 is connected, for example, to a cylinder or a solenoid-operatedvalve by screwing the male thread 22 into an unillustrated port of thecylinder, the solenoid-operated valve or the like.

[0021] A ring member 24 for tightening the connection site between thebody 12 and the connecting member 14 is fitted to the outercircumference of the body 12. The ring member 24 is made of a metalmaterial, and it is fitted to the outer circumferential surface of thebody 12 by being tightened at its outer circumferential section 26.

[0022] A first step section 28 and a second step section 30 are formedon the inner wall on the second end side of the body 12. A flange 36 ofa sleeve 34 for constructing an attachment/detachment mechanism 32 isengaged with the first step section 28. An inclined section 37 for beingfastened to the inner wall surface of the body 12 is formed on the outercircumference of the flange 36. A packing (seal member) 38 is installedto the second step section 30. The packing 38 abuts against a first endof a collet 40. As shown in FIG. 3, the collet 40 has a plurality ofslits 42 formed on its first end side.

[0023] A cylindrical guide member 44 is inserted between the outer wallat the second end of the collet 40 and the inner wall of the body 12. Acircumscribing expanded section 45 having a sharp cross section isformed on the outer circumference of the guide member 44. The expandedsection 45 bites into the inner wall surface of the body 12, and thusthe guide member 44 is prevented from disengagement from the body 12. Achuck 46, which is made of an elastic metal material to have asubstantially cylindrical configuration, is inserted into the collet 40.A fastening section 48, which bites into the outer circumferentialsurface of a fluid tube as described later on to fasten the fluid tube,is formed at a first end of the chuck 46. The chuck 46 has a pluralityof slits 50 which are formed on its first end side. Accordingly, thefastening section 48 of the chuck 46 is constructed such that it iselastically deformable in the radial direction.

[0024] A release bush 52 is inserted into the chuck 46. The release bush52 has a plurality of slits 54 formed at its first end, and its diameteris gradually reduced to make engagement with the fastening section 48 ofthe chuck 46. A flange 56, which protrudes radially outwardly, is formedat the second end of the release bush 52.

[0025] A pair of ring members 58 a, 58 b, which are separated from eachother by a predetermined spacing distance, are fitted to the outercircumferential surface of the body 12 provided with theattachment/detachment mechanism 32. Each of the ring members 58 a, 58 bis made of a metal material, and it is fitted to the body 12 by beingtightened at its outer circumference 60.

[0026] The number of the ring members 58 a, 58 b is not limited to two,which may be one or three or more.

[0027] The tube joint 10 according to the embodiment of the presentinvention is basically constructed as described above. Next, atightening apparatus 70 for tightening the ring member 24 will beexplained below on the basis of FIGS. 4 and 5.

[0028] As shown in FIG. 4, the tightening apparatus 70 is provided witha base pedestal 72. A circular base stand 74 is formed at a centralportion of the base pedestal 72. A columnar member 76 is secured to acentral portion of the base stand 74. A step section 78 for engagingwith the inner wall of the connecting member 14 is formed in thevicinity of the end of the columnar member 76. As shown in FIG. 5, aplurality of tightening members 80 are arranged on the base stand 74 sothat the columnar member 76 is surrounded thereby. The tighteningmembers 80 are provided such that they are slidable in the radialdirection of the base stand 74.

[0029] As shown in FIG. 5, the adjoining tightening members 80, 80 arearranged such that they are separated from each other by a gap 81 beforeperforming the tightening operation. Pin members 82 are secured to lowerportions of the tightening members 80. The pin members 82 are engagedwith grooves 84 formed on the base stand 74 so that the tighteningmembers 80 are prevented from rotation.

[0030] A circular arc-shaped projection 86, which protrudes toward thetube joint 10, is formed at an upper portion of each of the tighteningmembers 80. As shown in FIG. 6, a tightening section 88, which iscomposed of an annular recess for engaging with the ring member 24, isformed on the circular arc-shaped projection 86. Holding sections 90 a,90 b, which protrude forward toward the tube joint 10, are formed overand under the tightening section 88. The tightening sections 88 areformed such that they substantially coincide with the outercircumferential shape of the ring member 24 which is tightened when theplurality of tightening members 80 having been divided in the circulararc-shaped configuration in the circumferential direction are displacedtoward the tube joint 10 so that the adjoining tightening members 80abut against each other. A conical surface 92 is formed by the surfacesof the tightening members 80 disposed on the side opposite to thecolumnar member 76.

[0031] As shown in FIG. 4, a pressing member 94, which has asubstantially ring-shaped configuration to surround the tighteningmembers 80, is provided on the base pedestal 72. The pressing member 94has its inner wall surface 96 which is formed such that its diameter isgradually increased in the downward direction corresponding to theconical surface 92 of the tightening members 80. A plurality of guideshafts 98 are provided at lower portions of the pressing member 94. Theguide shafts 98 are provided such that they are insertable through guideholes 100 formed through the base pedestal 72. An unillustrated drivingsource such as a cylinder is connected to lower portions of the guideshafts 98. When the driving source is operated, the pressing member 94is displaced upwardly and downwardly.

[0032] Next, explanation will be made for a tightening apparatus 110 fortightening the ring members 58 a, 58 b of the tube joint 10. The sameconstitutive elements as those of the tightening apparatus 70 describedabove are designated by the same reference numerals, detailedexplanation of which will be omitted.

[0033] As shown in FIG. 7, a circular arc-shaped projections 111, whichis formed with each of the tightening members 80 of the tighteningapparatus 110, is provided with two tightening sections 112 a, 112 bcorresponding to the ring members 58 a, 58 b of the tube joint 10, thetwo tightening sections 112 a, 112 b being composed of a pair of annularrecesses formed to be substantially parallel to one another. Holdingsections 114 a to 114 d, which protrude forward toward the tube joint10, are formed over and under the tightening sections 112 a, 112 b.

[0034] The tightening apparatuses 70, 110 are constructed as describedabove. Next, their operations will be explained below.

[0035] The connecting member 14, the sleeve 34, the packing 38, thecollet 40, the guide member 44, the chuck 46, and the release bush 52are installed beforehand to the body 12 of the tube joint 10.

[0036] After completion of the preparatory stage as described above, thering member 24 and the ring members 58 a, 58 b are fitted to the body12. At this stage, the ring member 24 and the ring members 58 a, 58 bare not tightened.

[0037] Subsequently, as shown in FIG. 4, the inner wall of theconnecting member 14 of the tube joint 10 is engaged with the stepsection 78 formed on the columnar member 76 of the tightening apparatus70 so that the tube joint 10 is positioned on the tightening apparatus70.

[0038] Subsequently, the pressing member 94 is displaced downwardly inaccordance with the operating action of the unillustrated cylinder. As aresult, as shown in FIG. 8, the conical surface 92 of the tighteningmembers 80 is pressed by the inner wall surface 96 of the pressingmember 94, and the plurality of divided tightening members 80 aredisplaced toward the tube joint 10. During this process, the gaps 81between the adjoining tightening members 80, 80 are gradually decreased,and thus the tightening sections 88 are engaged with the outercircumference 26 of the ring member 24. In other words, the plurality oftightening members 80, which are divided to give the circular arc-shapedconfiguration, are displaced toward the center respectively inaccordance with the sliding action of the conical surface 92 of thetightening members 80 and the inner wall surface 96 of the pressingmember 94.

[0039] Therefore, the gaps 81 disappear in accordance with thedisplacement action of the tightening members 80, and thus the adjoiningtightening members 80, 80 abut against each other. As a result, thedivided tightening sections 88 make abutment to give a substantiallycircular configuration, and the tightening sections 88 press the outercircumference 26 of the ring member 24 over its entire circumferencesubstantially uniformly toward the center. Accordingly, the ring member24 is tightened, and it is deformed so that its diameter is decreased.Thus, the ring member 24 is fitted to the outer circumferential surfaceof the body 12 so that it bites into the body 12.

[0040] During this process, the ring member 24 undergoes deformation tomake expansion in the vertical direction. However, the upper and lowerportions of the ring member 24 are held by the holding sections 90 a, 90b of the tightening members 80. Accordingly, the deformation isregulated (see FIG. 6). Therefore, it is not feared that the ring member24 is extruded from the tightening sections 88. Further, the ring member24 is not deformed radially outwardly.

[0041] When the tightening operation for the ring member 24 iscompleted, the ring members 58 a, 58 b are subsequently tightened. Inthis case, the attachment/detachment mechanism 32 of the tube joint 10is installed to the columnar member 76 of the tightening apparatus 110.When the pressing member 94 is displaced downwardly, the plurality oftightening members 80 are displaced in the direction to make approach tothe tube joint 10. Accordingly, the tightening sections 112 a, 112 bpress the outer circumferences 60 of the ring members 58 a, 58 bsubstantially uniformly over the entire circumferences. Therefore, thering members 58 a, 58 b are tightened, and they are fitted so that theybite into the outer circumferential surface of the body 12 (see FIG. 7).

[0042] As described above, the ring members 24, 58 a, 58 b can beconveniently tightened with respect to the outer circumferential surfaceof the body 12 made of resin by using the tightening apparatuses 70, 110having the simple structures. As a result, it is possible to suppressthe production cost for producing the tube joint.

[0043] The tube joint 10, for which the ring member 24 and the ringmembers 58 a, 58 b have been tightened as described above, is installed,for example, to a cylinder or a solenoid-operated valve. In this case,the male thread 22 of the connecting member 14 is screwed into a port ofthe cylinder, the solenoid-operated valve or the like.

[0044] A fluid tube 102, which is formed with a passage 101 for allowingthe fluid to pass therethrough, is coupled to the attachment/detachmentmechanism 32. The fluid tube 102 is inserted between the sleeve 34 andthe release bush 52, and the first end of the fluid tube 102 is allowedto make abutment against the flange 36. In this state, when the fluidtube 102 is slightly pulled through the tube joint 10, the fasteningsection 48 of the chuck 46 bites into the outer circumferential surfaceof the fluid tube 102. If it is intended to disengage the fluid tube 102from the tube joint 10 in this state, the fastening section 48 furtherbites into the outer circumferential surface of the fluid tube 102.Therefore, the fluid tube 102 is reliably prevented from disengagement.On the other hand, when the flange 56 of the release bush 52 is pushedinwardly into the tube joint 10, the forward end of the release bush 52presses the fastening section 48 of the chuck 46 radially outwardly toincrease the diameter. Thus, it is possible to release the engaged statein which the fastening section 48 bites into the outer circumferentialsurface of the fluid tube 102. Accordingly, the fluid tube 102 can beeasily disengaged.

[0045] For example, even when the tube joint 10 is used in a hightemperature atmosphere, or even when a relatively high pressure isapplied to the inside of the tube joint 10 by the pressure fluid, thenthe body 12 is prevented from any deformation in the outward direction,because the body 12 is tightened with the ring member 24 and the ringmembers 58 a, 58 b. Therefore, it is possible to eliminate any fear ofdisengagement of the connecting member 14 and the fluid tube 102 fromthe body 12. Even when any external force such as shock is exerted onthe body 12, there is no fear of disengagement of the connecting member14 from the body 12.

[0046] The connection site between the body 12 and the fluid tube 102and the connection site between the body 12 and the connecting member 14are tightened by the ring members 24, 58 a, 58 b. Therefore, theconnection sites can be held more tightly in an air-tight orliquid-tight manner.

[0047] In the embodiment of the present invention, the connecting member14 is installed to the body 12 of the tube joint 10. However, it is alsoallowable that a thread section (not shown) is directly formedintegrally with the body 12 without installing the connecting member 14,and the thread section is screwed into an unillustrated port of acylinder or the like.

[0048] Further, in the embodiment of the present invention, the ringmembers 24, 58 a, 58 b are fitted around the outer circumferentialsurface of the body 12 by being tightened at their outer circumferences,however, it is also allowable that the ring members 24, 58 a, 58 b arefitted around the outer circumferential surface of the body 12 by beingpress-fitted.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A tube joint comprising: a body made of a resinmaterial having an edge and an opening at a second end of said body; anattachment/detachment mechanism into which a tube is configured to beinserted and which comprises: a sleeve provided in said opening at saidsecond end of said body; a release bush provided outside said sleeve,the tube being configured to be fitted onto said sleeve such that saidtube is inserted into an annular space formed between said sleeve andsaid release bush for allowing a fluid to flow through said tube intosaid opening at said second end; and an engaging member provided outsidesaid release bush and having a projection which outwardly projects froman outer circumferential surface of said engaging member and whichengages with an inner circumferential wall surface of said body at saidsecond end; and a ring member fitted to an outer circumferential wallsurface of said body at said second end, wherein a part of said body atsaid second end is tightly sandwiched between said ring member and saidengaging member, and said release bush is placed inside said engagingmember for preventing said tube in said annular space from beingdisengaged from said attachment/detachment mechanism.
 2. The tube jointaccording to claim 1, wherein said ring member presses the outercircumferential wall surface of said body radially inwardly.
 3. The tubejoint according to claim 1, wherein said sleeve has a flange facing anend surface of said tube in said annular space.
 4. The tube jointaccording to claim 1, wherein a connecting member, which is made of ametal material and which is adapted to be screwed into a port of apressure fluid driven apparatus, is coupled to a first end of said body,and another ring member made of metal which has its outer circumferencepressed radially inwardly so that said body and said connecting memberare prevented from disengagement, is fitted to said outercircumferential wall surface of said body coupled to sail connectingmember; and wherein said connecting member has at least one annularexpanded section for preventing the disengagement of said connectingmember from said body.
 5. The tube joint according to claim 1, whereinsaid attachment/detachment mechanism further includes a seal member forsurrounding an outer circumferential surface of said tube to prevent apressure fluid from leakage.
 6. The tube joint according to claim 1,further comprising: an additional ring member fitted to the outercircumferential wall surface of said second end of said body andpressing the outer circumferential wall surface of said body radiallyinwardly for preventing said body from being deformed, said additionalring member being positioned such that the projection of said engagingmember is located between the ring member and the additional ringmember.
 7. The tube joint according to claim 1, wherein said second enddoes not have any slits.
 8. A tube joint comprising: a body made of aresin material having a distal edge and an opening at a second end ofsaid body; an attachment/detachment mechanism into which a tube isconfigured to be inserted and which comprises: a fastening sectionconfigured to bite an outer circumferential surface of the tube; acollet having a taper section provided outside said fastening section;and an engaging member provided outside said taper section, saidengaging member having a projection which outwardly projects from anouter circumferential surface of said engaging member and which engageswith an inner circumferential wall surface of said body at said secondend: a ring member fitted to an outer circumferential wall surface ofsaid body at said second end, wherein said attachment/detachmentmechanism is constructed such that said engaging member engages withsaid taper section of said collet to press said fastening sectionradially inwardly toward the outer circumferential surface of the tubewhen a force is applied to the tube to pull out the tube from theattachment/detachment mechanism.
 9. The tube joint according to claim 8,wherein said ring member presses the outer circumferential wall surfaceof said body radially inwardly.
 10. The tube joint according to claim 8,wherein a connecting member, which is made of a metal material and whichis adapted to be screwed into a port of a pressure fluid drivenapparatus, is coupled to a first end of said body, and another ringmember made of metal which has its outer circumference pressed radiallyinwardly so that said body and said connecting member are prevented fromdisengagement, is fitted to said outer circumferential wall surface ofsaid body coupled to said connecting member; and wherein said connectingmember has at least one annular expanded section for preventing thedisengagement of said connecting member from said body.
 11. The tubejoint according to claim 8, wherein said attachment/detachment mechanismfurther includes a seal member for surrounding an outer circumferentialsurface of said tube to prevent a pressure fluid from leakage, and arelease bush inserted into a chuck to release a fastened state of saidfastening section with respect to said tube.
 12. The tube jointaccording to claim 8, further comprising: an additional ring memberfitted to the outer circumferential wall surface of said second end ofsaid body and pressing the outer circumferential wall surface of saidbody radially inwardly for preventing said body from being deformed,said additional ring member being positioned such that the projection ofsaid engaging member is located between the ring member and theadditional ring member.
 13. The tube joint according to claim 8, whereinsaid second end does not have any slits.
 14. A tube joint comprising: abody made of a resin material having a distal edge and an opening at asecond end of said body; an attachment/detachment mechanism into which atube is configured to be inserted and which comprises: a fasteningsection configured to bite an outer circumferential surface of the tube;a collet having a taper section provided outside said fastening section;and an engaging member provided outside said taper section, saidengaging member having a projection which outwardly projects from anouter circumferential surface of said engaging member and which engageswith an inner circumferential wall surface of said body at said secondend: a ring member fitted to an outer circumferential wall surface ofsaid body at said second end and pressing the outer circumferential wallsurface of said body radially inwardly, wherein saidattachment/detachment mechanism is constructed such that said engagingmember engages with said taper section of said collet to press saidfastening section radially inwardly toward the outer circumferentialsurface of the tube when a force is applied to the tube to pull out thetube from the attachment/detachment mechanism; and wherein said ringmember presses the outer circumferential wall surface of said bodyradially inwardly, and said taper section of said collet engages with anend surface of said engaging member to press said fastening section forpreventing said engaging member from being disengaged from said body.15. The tube joint according to claim 14, wherein a connecting member,which is made of a metal material and which is adapted to be screwedinto a port of a pressure fluid driven apparatus, is coupled to a firstend of said body, and another ring member made of metal which has itsouter circumference pressed radially inwardly so that said body and saidconnecting member are prevented from disengagement, is fitted to saidouter circumferential wall surface of said body coupled to saidconnecting member; and wherein said connecting member has at least oneannular expanded section for preventing the disengagement of saidconnecting member from said body.
 16. The tube joint according to claim14, wherein said attachment/detachment mechanism further includes a sealmember for surrounding an outer circumferential surface of said tube toprevent a pressure fluid from leakage, and a release bush inserted intoa chuck to release a fastened state of said fastening section withrespect to said tube.
 17. The tube joint according to claim 14, furthercomprising: an additional ring member fitted to the outercircumferential wall surface of said second end of said body andpressing the outer circumferential wall surface of said body radiallyinwardly for preventing said body from being deformed, said additionalring member being positioned such that the projection of said engagingmember is located between the ring member and the additional ringmember.
 18. The tube joint according to claim 14, wherein said secondend does not have any slits.